Modern Vespa

I am driving my 2001 ET4 150 from New Orleans to San Francisco. I am making multiple stops to and from. The total distance is over 5000 mi. She currently has 15,000 mi. I am going to rebuild the engine. Any help on what should be done? I plan to leave the bottom end alone. Only replacing the cylinder head and using the Mallosi 190cc cylinder kit. THX!!

I kitted my LX a couple of years ago and wrote up a series of pictorial tutorials over in the Project Reports section. This should all be applicable for an ET4. I also installed a Polini upgear kit at the same time. Here are the links:

https://modernvespa.com/forum/topic60089?highlight=part
https://modernvespa.com/forum/topic60208?highlight=part
https://modernvespa.com/forum/topic60475?highlight=part
https://modernvespa.com/forum/topic60710?highlight=part

As I continue to experiment with finding optimal variator tuning, I have never gotten around to writing up Part 5.

i followed silver's posts and really will take you through step by step.
good luck

Nice thread.
I too am going to up my cc's in my ET4 and wanted to mark this thread so I can come back to it when I need to.
Thanks for posting up the info.
Mega.

I bought my ET4 with from my sister with 14,000 mi. She rode it hard and put it away wet, so it has been a rough 14,000 mi. I've put 1,000 mi on it with no problems, but I really don't want a failure trying to get across the never ending Texas. I plan on keeping it for a while and don't mind the investment. I need durability. This thing is going to be wide open for hours on end for days on end. What exactly is the top end failure that seems to be common on higher mileage engines? Is it a cracked head or a cylinder failure? The bottom end seems to be pretty stout. Is this correct?

Well, it is the same bottom end that is used on the GT200, so it can reliably handle more horsepower than your kit will generate.

I've never had a top-end failure on either of my Leader engines, so can't provide any anecdotal info there. My kitted LX has been dead reliable for 13,000 miles or so, including a trip from Maryland to Colorado and back in 95+ degree heat and many other short tours of a few hundred miles. No signs of drop-off in power or increased oil consumption.